P0898: Transmission Control System Malfunction Indicator Lamp Request Circuit Low
What to do
The warning lamp is stuck on and no longer tells you anything — it will look identical if a real fault develops. Worth repairing for that reason as much as any other, and it will fail an emissions test as it stands.
What this code means
The circuit by which the transmission module requests the warning lamp is held low, normally a short to ground, which the engine module reads as a permanent request. The lamp is therefore illuminated continuously regardless of whether anything is wrong with the transmission.
That is worse than it sounds, for the same reason a smoke alarm that sounds constantly is worse than one that is merely broken: a warning lamp that is always on carries no information, and it will still be on when something genuinely does go wrong. It also fails an emissions test on its own.
Likely causes
Start here
- Wiring shorted to ground · moderate
- Corroded or loose connector · easy
Less common
- Faulty transmission control module · specialist
- Poor module ground connection · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0898.